Resurrection of a diatom after 7000 years from anoxic Baltic Sea sediment.

Dormancy is a widespread key life history trait observed across the tree of life. Many plankton species form dormant cell stages that accumulate in aquatic sediments and, under anoxic conditions, form chronological records of past species and population dynamics under changing environmental conditions. Here we report on the germination of a microscopic alga, the abundant marine diatom Skeletonema marinoi Sarno et Zigone, that had remained dormant for up to 6871 ± 140 years in anoxic sediments of the Baltic Sea and resumed growth when exposed to oxygen and light.

Quantitative real-time PCR assays for species-specific detection and quantification of Baltic Sea spring bloom dinoflagellates.

In the Baltic Sea, the dinoflagellates , , and are important contributors to the spring bloom. However, their relative contribution to the bloom community cannot be unambiguously determined by conventional light microscopy due to a lack of resolution of distinctive morphological features of the three species. Here, we describe a molecular approach based on a quantitative real-time polymerase chain reaction (qPCR) primer and probe system, targeting the ITS1 and ITS2 regions of the rRNA gene for all three species and enabling their quantification.

Population genomic analyses reveal that salinity and geographic isolation drive diversification in a free-living protist.

Protists make up the vast diversity of eukaryotic life and play a critical role in biogeochemical cycling and in food webs. Because of their small size, cryptic life cycles, and large population sizes, our understanding of speciation in these organisms is very limited. We performed population genomic analyses on 153 strains isolated from eight populations of the recently radiated dinoflagellate genus Apocalathium, to explore the drivers and mechanisms of speciation processes.

Local adaptation through countergradient selection in northern populations of .

Marine microorganisms have the potential to disperse widely with few obvious barriers to gene flow. However, among microalgae, several studies have demonstrated that species can be highly genetically structured with limited gene flow among populations, despite hydrographic connectivity. Ecological differentiation and local adaptation have been suggested as drivers of such population structure.